let btn = document.getElementById("ok");
btn.disabled = true;
let t = 5;
function count()
{
t--;
;
btn.innerHTML = "剩余时间 "+ t + "秒";
if (t <= 0) {
clearInterval(id);
btn.innerHTML = "剩余时间0秒";
btn.disabled = false;
let url = window.location; 
window.location = "https://www.wust.edu.cn";
}
}
let id = setInterval(count, 1000);


 